var dns = require('dns');

dns.lookup('github.com', function onLookup(err, address, family) {
	console.log('ip addr:', address);
	dns.reverse(address, (err, hostnames) => {
		if (err) {
			console.log(err.stack);
		}
		console.log('nslookup =>', address, JSON.stringify(hostnames));
	});
});
